The processing of fluids can occur in many different fields for many different applications. It is often necessary or desirable in the processing of fluids to switch from one flow path to another. It is also often necessary or desirable in the processing of fluids to utilize centrifugal force as the mechanism for enhancing the fluid flow. For example, one may wish to filter fluids to determine different components or constituents of a sample, to separate fluids, to concentrate fluids, and the like. In each of these applications, the fluids often must be passed through different separating media, filters or dividers. Also, sufficient driving force must be provided to attain the flow rates desired.
In one application, for example, the analysis of samples, particularly biological samples, i.e., physiological fluids such as whole blood, serum or urine, one must separate or extract the desired components from the sample. Analytical procedures that typically require this step include trace organic and inorganic analyses for environmental control in such areas as monitoring industrial effluents, pesticide run-off and drinking water; impurity and formulation analyses in the food and pharmaceutical industries and process monitoring in many industrial operations. Typically, these analyses require that the extraction or separation step be performed manually. Once the extraction is made, the extracted or separated components of the desired material can be analyzed by any known technique such as thin-layer chromatography, liquid chromatography, gas chromatography, and the like.
One such extraction technique is described by Quame in U.S. Pat. No. 3,567,029. Quame describes the use of a disposable separating column filled with a particular solid phase, capable of extracting certain lipophilic compounds, including the most commonly encountered abused drugs, such as phenobarbital, amphetamine, methadone and the like, In a typical drug extraction, such as from a urine sample, Quame allows the urine sample to pass through the column. The column selectively adsorbs any lipophilic drugs contained in the urine, thereby extracting the lipophilic drugs from the aqueous phase. Next, the adsorbed drugs are eluted from the column by a solvent and any residual aqueous phase is retained by a filter. This technique worked quite well for some urine samples. Unfortunately, however, it is somewhat time consuming because it is manual and because the sample and the solvent phases slowly pass through the column and filter combination.
Another technique for assaying fluids is that described by Shapiro et al. in U.S. Pat. No. 3,953,172. Shapiro uses a swinging bucket centrifuge rotor with the buckets each holding a separating column. The fluid samples to be assayed are mixed with a reagent at the central part of the centrifuge rotor and then allowed to pass, under the influence of centrifugal force, through the single separating column. While Shapiro does have the advantage of using centrifugal force to speed up the process, it is still limited somewhat in application, in that multiple solvents cannot readily be used. It is therefore difficult to recover materials adsorbed on the column. It is difficult to concentrate the desired materials for later analyses. No fluid switching is provided, i.e., no means is provided to permit different fluids flowing through a separating column to pass to different collecting vessels. Conceivably, this might be accomplished by various valving arrangements, but such becomes relatively complex and, in any event, apparently has never been accomplished.
It is therefore an object of this invention to provide an improved method for processing fluid materials.
Another object of this invention is to provide an improved apparatus for processing fluid materials.